When d2i_ECPrivateKey reads a private key with a missing (optional)
public key, generate one automatically from the group and private key.
(Imported from upstream's 2083f7c465d07867dd9867b8742bb71c03d1f203)
Change-Id: I9e5090de87cf846ab92e4be5b6bf64e6091d02e4
Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta).
(This change contains substantial changes from the original and
effectively starts a new history.)